Halliburton's employees work at a three wellhead fracking site Monday, June 26, 2017, in Midland. ( Steve Gonzales / Houston Chronicle )

Halliburton's employees work at a three wellhead fracking site Monday, June 26, 2017, in Midland. ( Steve Gonzales / Houston Chronicle )

Photo: Steve Gonzales/Houston Chronicle

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Ali Daneshy, president of Daneshy Consulting.

Ali Daneshy, president of Daneshy Consulting.

Photo: Courtesy Photo

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Interaction between wells can boost production

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Fracture-driven interactions between horizontal wells often have troublesome outcomes. But completely avoiding interaction also could bring trouble, according to an adjunct professor of petroleum engineering at the University of Houston.

“Don’t avoid interaction, try to minimize the negative effects,” says Ali Daneshy, who also is president of Daneshy Consulting.

Interaction between wells can mean operators get a lot more oil out of the reservoirs, he said in a phone interview from his Houston office.

Daneshy addressed the February luncheon of the Permian Basin section, Society of Petroleum Engineers, which has been focusing on fracturing technology this month.

The negative impact is well-known and is something every operator has experienced and is concerned about, he said. Pressure from what he calls the primary well communicates with what he calls the infill well, or fluids from the primary well will find their way into the infill well and can damage the infill wells.

“When they do this, it changes the production in that (infill) well. Sometimes it goes across two or three wells,” Daneshy said.

Aside from interfering with production, he said operators could have trouble drilling infill wells because they’re intercepting fractures from other wells and could lose drilling mud or cementing fluids.

“It could also create legal issues if the wells have different owners,” he said.

“If you’re drilling horizontal wells, interaction happens all the time,” Daneshy said. “The most significant cause is the well that is producing depletes the reservoir. That depleted reservoir draws fractures toward it. So a frac from an infill well will go towards the primary well.”

The solution would be simulfracturing: fracturing the primary and infill wells at the same time to avoid depleting the reservoir, he said. He also recommends zipper fractures, in which frac crews go back and forth between multiple wells. The most important element is to not deplete the reservoir, he said.

And if an operator is drilling near another operator, “before there is a question of interference, the two sides should reach an agreement beforehand on sharing the production,” he said.